Enhanced magnetocaloric effect in terbium-doped gadolinium oxide nanoparticles

A simple, solvothermal method has been used to synthesize gadolinium oxide nanoparticles with 3 wt% terbium doping (3% Tb-doped Gd2O3). The particles have cubic crystal structure (Space group I alpha-3, No. 206). The mean particle size estimated from transmission electron microscopy is similar to 55 nm and the crystallite size estimated from powder X-ray diffraction data is similar to 28 nm. The sample, 3% Tb-doped Gd2O3, remains paramagnetic from 300 K down to 5 K. Magnetocaloric effect (MCE) is estimated in terms of isothermal magnetic entropy change (Delta S-m) at low temperatures. The maximum value of Delta S-m at 6 K for 70 kOe field change is found to be about -20.9 Jkg(-1)K(-1). This value is quite large and is comparable with that of pristine nanosized Gd2O3. Therefore rare earth-doped Gd2O3 nanostructures could also be useful in low temperature magnetic refrigeration.